The lichenicolous Phoma species on Cladonia are revised. A statistical analysis of the conidial size suggests that three species are involved: P. cladoniicola sp. nov. a common and widespread species in the Northern Hemisphere occurring on a wide range of Cladonia species; P. foliaceiphila sp. nov. known from C. foliacea and C. fimbriata in Europe; and P. grumantiana sp. nov. known from C. symphycarpia and C. mateocyatha in Svalbard and the USA.

The first lichen-forming species of Psammina, P. palmata sp. nov., is described from decorticate oak in West Suffolk (UK). It is distinguished from other species by the palmate and 2–3-order branched non-septate conidia flattened in a single plane. The conidia recall those of the lichen-forming hyphomycete genus Cheiromycina in some respects, but do not originate from the swollen subglobose cells characteristic of that genus. The generic concepts in this complex of algicolous, lichen-forming, lichenicolous, and saprobic fungi are discussed, and it is concluded that Pycnopsammina should be treated as a synonym of Psammina as the conidiogenesis resembles that of the type species of Psammina, which also has rather similar conidiomata; the combination Psammina lobariae comb. nov. (syn. Pycnopsammina lobariae) is therefore made. A key to the eight species now accepted in the genus is provided, which now includes algicolous, lichen-forming, lichenicolous, and plant saprobic species.

Phoma fuliginosa sp. nov. is described and illustrated from apothecia of Caloplaca trachyphylla (Teloschistaceae) collected in Nebraska, USA. The species is distinguished from other lichenicolous fungi referred to the genus in the shape and size of the conidia. It is considered pragmatic to continue to use the generic name Phoma for this group of lichenicolous coelomycetes until cultural and molecular information is available, although these fungi may later prove not to be congeneric amongst themselves nor with the species occurring on plants. A key to the 14 lichenicolous species now accepted in Phoma is provided, and notes on reports of some additional collections referred to the genus are included.

Lichenoconium christiansenii sp. nov. is described and illustrated from the apothecia of Nodobryoria abbreviata (syn. Bryoria abbreviata) in Washington State, USA. The species recalls L. lichenicola, but differs in the more subglobose conidia and the shorter conidiogenous cells as well as in occurring on a different host. A key to the 14 species now known in the genus is provided. Lichenoconium cargillianum is also reported from Letharia vulpina for the first time.

Since the last compilation in 1983, the number of lichenicolous fungi (and lichenicolous lichens) recorded in Great Britain and Ireland has increased from 218 to 403 species (a rise of 85%). The introduction includes accounts of: the history of investigation, circumscription, phylogenetic relationships, symbiotic interactions, dispersal and establishment, distribution, culture, host restriction, and identification. The checklist enumerates the recorded species. Information is provided on the systematic position of each genus, together with the authors and dates of publication of all accepted names; synonyms used in the literature of the two countries since 1910 are cross-indexed. References to pertinent literature with descriptions and discussions are included, together with notes on particular species. The list of references cited includes 298 publications. The following new scientific names are introduced: Diederichia gen. nov., and Dactylospora scapanaria (syn. Lecidea scapanaria), Diederichia pseudevemiae (syn. Macrophomina pseudeverniae), Muellerella ventosicola (syn. Microthelia ventosicola) and Nigromacula uniseptata (syn. Vouauxiella uniseptata) combs, nov.